The scanning for this study is done with an imaging procedure in the department of Nuclear Medicine during which the experimental drug [124 I] PSCA-Minibody will be administered by intravenous (i.v.) infusion. An experimental drug is one that is not yet approved by the US Food and Drug Administration (FDA). [124 I] PSCA-Minibody is a combination of a monoclonal antibody, and I-124, a radioactive type of iodine. The iodine will make the antibody and the cancer cells visible in a PET scan. PET stands for positron emission tomography and uses radioactivity to image the inside of the body. A CT scan uses x-rays to look at the internal organs in the body. This study will use a combination PET/CT to look at the cancer cells in your body that have taken up the study agent as well as to see their location in your body.